The purpose of this study is to conduct an epidemiological study of psychiatric disorders and service utilization in Native American adolescents. In particular, the relationship between substance abuse and other psychiatric disorders will be investigated. In general, adolescents have rates of psychiatric disorders as high as those of adults, while a number of serious psychiatric disorders show a high likelihood of adolescent age of onset. Further, the early appearance of certain psychiatric disorders is associated with elevated rates of other, co-morbid psychiatric disorders. Despite increases in knowledge about adolescents in general, very few methodologically rigorous studies of psychiatric and help-seeking characteristics of Indian adolescents have been conducted. What little literature exists indicates that Native American youth experience high rates of psychiatric disorders and have lower access and utilization of mental health services. The proposed study will involve the study of three groups of Native American adolescents in three service areas: the Navajo Nation, the Mississippi Band of the Choctaw Indians, and the Michigan tribes of the Bemidji Service area. Advisory councils from each of these three areas will provide consultation throughout the study. Initially, the project will involve a pilot study with 500 youth to examine the cultural appropriateness of selected instruments and procedures. As a result of this pilot study, necessary revisions in instruments and procedures will be implemented in a study of 3,000 adolescents, of whom 500 will be institutionalized youth. During both phases of the study, a multi-stage cluster sample will be identified in two areas to provide an adequate sample; in the third area, a census will be implemented. In addition to ascertaining rates of psychiatric disorders, co-morbidity of psychiatric disorders, and service access and utilization, the study will also examine the relationship between psychosocial adversity and resources to each of these characteristics.